public static async Task ResetFaceLists()
        {
            faceLists = new Dictionary <string, FaceListInfo>();

            try
            {
                IEnumerable <FaceListMetadata> metadata = await FaceServiceHelper.GetFaceListsAsync(FaceListsUserDataFilter);

                foreach (var item in metadata)
                {
                    await FaceServiceHelper.DeleteFaceListAsync(item.FaceListId);
                }
            }
            catch (Exception e)
            {
                ErrorTrackingHelper.TrackException(e, "Error resetting face lists");
            }
        }
        public static async Task Initialize()
        {
            faceLists = new Dictionary <string, FaceListInfo>();

            try
            {
                IEnumerable <FaceListMetadata> metadata = await FaceServiceHelper.GetFaceListsAsync(FaceListsUserDataFilter);

                foreach (var item in metadata)
                {
                    faceLists.Add(item.FaceListId, new FaceListInfo {
                        FaceListId = item.FaceListId, LastMatchTimestamp = DateTime.Now
                    });
                }
            }
            catch (Exception e)
            {
                ErrorTrackingHelper.TrackException(e, "Face API GetFaceListsAsync error");
            }
        }